[PATCH 1/2] Revert "futexes: Remove rw parameter from get_futex_key()"

[KOSAKI Motohiro]

This reverts commit 7485d0d3758e8e6491a5c9468114e74dc050785d.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
---
 kernel/futex.c |   27 +++++++++++++++------------
 1 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index fe28dc2..1a91ea2 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -218,6 +218,8 @@ static void drop_futex_key_refs(union futex_key *key)
  * @uaddr:	virtual address of the futex
  * @fshared:	0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
  * @key:	address where result is stored.
+ * @rw:		mapping needs to be read/write (values: VERIFY_READ,
+ *		VERIFY_WRITE)
  *
  * Returns a negative error code or 0
  * The key words are stored in *key on success.
@@ -229,7 +231,7 @@ static void drop_futex_key_refs(union futex_key *key)
  * lock_page() might sleep, the caller should not hold a spinlock.
  */
 static int
-get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
+get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
 {
 	unsigned long address = (unsigned long)uaddr;
 	struct mm_struct *mm = current->mm;
@@ -252,7 +254,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
 	 *        but access_ok() should be faster than find_vma()
 	 */
 	if (!fshared) {
-		if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
+		if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
 			return -EFAULT;
 		key->private.mm = mm;
 		key->private.address = address;
@@ -261,7 +263,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
 	}
 
 again:
-	err = get_user_pages_fast(address, 1, 1, &page);
+	err = get_user_pages_fast(address, 1, rw == VERIFY_WRITE, &page);
 	if (err < 0)
 		return err;
 
@@ -940,7 +942,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
 	if (!bitset)
 		return -EINVAL;
 
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_READ);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -986,10 +988,10 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
 	int ret, op_ret;
 
 retry:
-	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1);
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
 	if (unlikely(ret != 0))
 		goto out;
-	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
 	if (unlikely(ret != 0))
 		goto out_put_key1;
 
@@ -1243,10 +1245,11 @@ retry:
 		pi_state = NULL;
 	}
 
-	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1);
+	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
 	if (unlikely(ret != 0))
 		goto out;
-	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
+			    requeue_pi ? VERIFY_WRITE : VERIFY_READ);
 	if (unlikely(ret != 0))
 		goto out_put_key1;
 
@@ -1790,7 +1793,7 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
 	 * while the syscall executes.
 	 */
 retry:
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, VERIFY_READ);
 	if (unlikely(ret != 0))
 		return ret;
 
@@ -1941,7 +1944,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect,
 	}
 
 retry:
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, VERIFY_WRITE);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -2060,7 +2063,7 @@ retry:
 	if ((uval & FUTEX_TID_MASK) != vpid)
 		return -EPERM;
 
-	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key);
+	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_WRITE);
 	if (unlikely(ret != 0))
 		goto out;
 
@@ -2249,7 +2252,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	debug_rt_mutex_init_waiter(&rt_waiter);
 	rt_waiter.task = NULL;
 
-	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
 	if (unlikely(ret != 0))
 		goto out;
 
-- 
1.7.3.1


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